Supramolecular Templation of Entanglements in Organogels

Polymer entanglements─topological constraints to chain motion─are fundamental features of polymers, whose presence is believed to improve materials properties such as modulus and toughness, essential for most applications of soft materials. However, precise examination of the relationship between how the chains are entangled and material properties has remained elusive due to both difficulty in synthesizing materials with controlled entanglement topologies and an inability to spectroscopically detect the entanglements within the resulting polymer. Here, we use phenanthroline–copper(I) complexes as supramolecular templates installed in a poly(ethylene glycol) (PEG) network to form organogels with templated entanglements. When coordinated with copper, the storage moduli of both the entangled and the control materials are comparable to one another. Upon copper removal, unveiling the trapped entanglements, the gels with templated entanglements have a storage modulus 50–91% greater than the controls. Additionally, we discovered that both "entangled" and control gels form a fluorescent phenanthroline-based exciplex upon removal of solvent, indicative of proximity of phenanthroline moieties.